My 2nd attempt at noise reduction of Streety's footstep.flac. I used a notch filter at 50 Hz and harmonics, also I extracted some noise from a gap between footsteps and used it as a profile in a noise reduction algorithm lightly applied to the whole, and I applied some dynamics processing. Also, I manually rounded off the peaks of all the clipped over-recorded sections (a bit of a cheat but there you are). Some of the natural resonance of the narrow hall has been lost. Cool Edit Pro.